1. Field of the Invention
This invention is in the field of automatic washing machines employing vertical axis agitators which oscillate to provide a tumbling or generally toroidal motion to the clothes in washing the clothes contained within the machine and provides an agitator construction which is particularly useful with large or heavy clothes loads to improve the movement of the clothes within the machine and thereby the washing action.
2. Description of the Prior Art
It has long been appreciated that the most efficient clothes movement pattern for washing clothes within an automatic washing machine having a vertical axis agitator is a pattern which provides a rollover of the clothes which involves moving the clothes down the agitator barrel, then radially outward from the oscillating agitator vanes, upward along the wall of the tub, and inward to the barrel. Conventional washing machines are reasonably proficient in achieving this type of rollover pattern when light loads are being washed, but not with heavy loads. When the washing basket is tightly packed with clothes, the load crowds the agitator and the basket area. A conventional oscillating agitator has difficulty in attaining any kind of a rollover to the clothes load under these conditions. The conventional-type agitator then scrubs merely the bottom portion of a tightly-packed heavy load, resulting in a very poor uneven cleaning action.
There are a few examples in prior patents of agitators which move in separate paths during a washing operation. For example, the Bryant U.S. Pat. No. 1,834,936 suggests dual agitator members which are reciprocated in opposite directions within the tub, the object being to create a violent water action.
The Krolzick U.S. Pat. No. 3,678,714 assigned to the same assignee as the present invention described a washing machine assembly including a pair of agitators, the two agitators being coupled together for mutual oscillation, but having cam means or the like provided between the two agitators to effect a vertical reciprocation of one with respect to the other during such oscillation.
Prior art patents disclose agitators with spiral vane elements. For example, Dyer U.S. Pat. No. 2,331,897 discloses a washing machine having an agitator provided with a spiral vane on an upper portion, the agitator rotating at motor speed during washing.
Krolzick U.S. Pat. No. 196,194 assigned to the same assignee as the present invention shows an agitator for a laundry machine wherein the ornamental design for the agitator includes a spiral vane arrangement.
Geldhof U.S. Pat. No. 2,734,367, assigned to a predecessor of the assignee of the present invention, shows an agitator for a laundry machine wherein the agitator includes spiral vanes which extend in the form of radial vanes on their lower edges with radial projections or vanes extending intermediate the spiral vanes.
Flexible agitator vanes have been used in combination with an agitator skirt portion as in U.S. Pat. No. 3,307,383 to Cobb et al assigned to the assignee of the present invention. That patent shows flexible vanes attached to the center agitator post and spaced above a skirt to reduce tangling of fabrics on the agitator vanes.
Walton U.S. Pat. No. 3,112,632 discloses an agitator having a ribbed and grooved agitator barrel and flexible vanes for reducing tangling of clothing on such vanes during oscillation of the agitator.
U.S. Pat. No. 3,381,504 to Smith shows flexible vanes attached to the center agitator post and spaced above a skirt with the spacing increasing toward the outer periphery of the skirt.
U.S. Pat. No. 3,608,110 to Hubbard et al shows an agitator assembly having small upper vanes connected to lower vanes by helical vane sections, the lower vanes being substantially flexible. The entire agitator having the three classes of vanes oscillates back and forth together with the skirt lying beneath but unattached to the lower vanes, in an attempt to achieve a toroidal movement of clothing and washing fluid in the washing tub.
The following additional references are part of the prior art for consideration in connection with the present invention.
______________________________________ Altorfer 1,704,932 3/1929 Maus 2,021,097 11/1935 Skinner 2,253,989 8/1941 Castner 2,502,702 4/1950 Byrd et al. 3,117,434 1/1964 Bochan 3,285,040 11/1966 ______________________________________
In general, the prior art has provided agitators having only oscillatory motions, attempting to achieve good rollover of clothing in the washing tub by increasing the vigor of the agitation.
In contrast, the co-pending application of Platt, the present applicant, U.S. Ser. No. 595,792, assigned to the assignee of the present application, discloses a double acting auger agitator comprising a combination oscillating and unidirectional agitator for an automatic washer, having a unidirectional auger provided with a helical vane and one set of oscillating lower or scrubbing vanes.
Double acting auger agitators of the type generally disclosed in the above-mentioned application Ser. No. 595,792, of Platt include a vaned lower agitator element mounted for oscillating motion about an axis of a washer and an upper agitator element mounted for unidirectional rotation about the same axis, the upper auger agitator element having helical vane means associated therewith for forcing or deflecting clothes in the washer adjacent the upper agitator element downward toward the oscillating vanes on the lower portion of the agitator. The described operation of the auger agitator is effective to promote the desired continuous rollover movement of the clothes and fabrics undergoing washing, resulting in improved and more uniform washability of the clothes load.
Additionally, a co-pending application by Ruble, U.S. Ser. No. 575,730, filed May 8, 1975, assigned to the assignee of the present invention, discloses a double acting auger agitator comprising an oscillating vertical-axis agitator in combination with an agitator accessory having a sleeve for mounting on the agitator and a helical vane projecting from the sleeve in the form of an auger. The auger agitator accessory is rotated in one direction via a one-way clutch during one-half cycles of the oscillating agitator.